I have the X-Grip and tether I can sell you!! I decided not to use it because my S7 would not sit correctly without the side buttons being pushed.
I used it for a day and then removed it.
PM me if interested. It is the X-Grip and a tether similar to this only. NO MOUNT OR STEM INCLUDED.
It's actually a rubber band used to attach your phone to a bike mount, here:
https://www.amazon.com/dp/B017STJY4I?ref=ppx_pop_mob_ap_share